Connector for electric cables



July 17, 1956 K. A. SMYERS CONNECTOR FOR ELECTRIC CABLES Filed April 20,1953 United States This invention concerns a connector for electricalwires carrying electrical impulses for the propagation of sound.

The principal use of this connector is for securely holding and clampingelectrical connectors carrying audio impulses through wires whichinclude a central stranded conductor and insulating sheath surroundingthis and a sheath of metallic braided wires surround the insulationsheath. This structure may be included within a second insulationcovering. 7

One of the objects of the invention is to provide a connector which willhold stranded wire of the type above mentioned securely and firmly sothat the contacts within the connector can not be loosened by ordinaryrough usage or even extraordinary abuse.

A second object is to provide a compact connector having metallic bodywhich will securely hold flexible electric cable and provide securecontacts with a central conductor within the cable and a flexiblemetallic sheath outside of the central conductor.

1 attain the foregoing objects by means of the particular construction,devices and combination of parts shown in the accompanying drawings inwhich Figure 1 is a side elevational center section of the connector inassembled form and with a stranded cable held in place.

Figure 2 is a transverse section of the connector taken substantially online 2-2 of Figure 1.

Figure 2a is a transverse section taken substantially on line 2--2 ofFigure 1 but showing the holding keys in an expanded position to releasethe cable.

Figure 3 is a transverse section taken substantially on line 3-3 ofFigure 1; and

Figure 4 is a plan view of the inner end portion of the head bolt andlock nut which hold the stranded conductor.

Similar numerals refer to similar parts in the several views.

The body 3 of the connector is made of metal and has a bore 20 at theouter or connecting end and a bore 24 at the inner or cable clampingend. The end portions of both bores are threaded. An end plug 1 threadsinto the end of bore 24 and is provided with a central hole 18 at itsouter end to receive cable 17, an outwardly extending bore 18a toreceive keys 2, and a taper bore 22 joining bores 18a and 18. Theunbored space between bores 20 and 24 is centrally drilled with a smallhole 19 to receive the inner portion of cable 17.

Head 4 is threaded into the outer end of bore in body 3. This headcarries a head bolt connector 9 which is centrally positioned byinsulating washers 6 and 7 which are secured by axial conductor screw 8.When head bolt connector 9 is secured in head 4 and the latter threadedinto body 3 the head bolt connector is concentrically positioned withina central inwardly opening bore 4a of head 4 and securely kept out ofcontact with the metal body portion of said head.

The inner end of head bolt connector 9 is reduced in size and providedwith a threaded portion 9a which has a longitudinal groove 12 to receivethe stranded lead atent- Q ice wire 14. At the base of threads 9a thereis a taper or angular annular shoulder 11. The lock nut 10 screws on tothreads at 9a and holds the end portion of lead wire 14 in place ingroove 12 and clamps it against tapered shoulder 11. This nut has atapered inner face 23 which conforms to shoulder 11 and clamps the endof conductor 14 securely against shoulder 11.

At the cable clamping end of body 3 and in order to firmly secure cable17, I provide two keys indicated by numerals 2, 2. These keys arebeveled from their outer edges toward their inner edges at each end andslidably fit into grooves 13, which may be termed key way slots,

and are formed on the inner annular face of bore 24 of body 3.

At the inner end of bore 24 there is a taper 21 which is aligned withthe taper 22 within the central bore of end plug 1. When end plug 1 isscrewed into the threadthe braided'wire sheathing 16 of cable 17. Sincethe inner faces of keys 2 can be made long relative to the diameter ofbody 3 an adequate clamping surface is provided so that the clampedportion of cable 17 is securely held. This clamping action securelyholds the sheathed portion 16 of the cable, and also grounds it to thebody 3. The outer insulated portion of cable 17 extends out: wardthrough hole 18.

The outer end of head 4 is enlarged and threaded to. hold attachingcollar 5, when desired, or to permit it to thread onto a male connectorplug 5a (shown in dotted lines). Collar 5 may also be threaded inwardlyover and beyond the threads on head 4 so that it loosely surrounds body3, and a female connector (not shown) may be screwed onto the threads onhead cap 4.

In use the outer insulated covering of cable 17 is removed to expose alength of the braided wire sheathing 16 sufiicient to contact keys 2.The insulation 15 on the end portion of the cable is then removed for adistance sufficient to expose the stranded lead wire 14 to fit intogroove 12 on head bolt 9 and to extend over the tapered shoulder 11.Sufiicient insulation 15 remains to extend through hole 19 and insulatethe lead 14 from body 3.

Head 4 is removed from body 3 and end plug 1 and, body 3, in untightenedrelation, are then slipped onto cable 17.

The exposed stranded conductor 14 is held in groove 12 and againstshoulder 11 While lock nut 10 is tightened, to make a secure mechanicaland electrical connection to bolt 9. The lead Wire 14 is thus connectedto the head. bolt 9 and axial conductor screw 8. After the abovedescribed lead wire connection is made body 3 is brought toward head 4and threaded onto it. During this process the keys 2 are loose and inopened position as shown in Figure 2a. After body 3 is threaded ontohead 4 the keys are clamped onto the exposed stranded sheathing 16 ofcable 17 by tightening end plug 1 in the threaded inner end of bore 24.When these keys tighten onto this portion of the cable they hold theentire cable firmly in place. The stranded lead 14, is maintainedstraight and substantially taut as shown in Figure 1, so that it doesnot contact body 3. Also, the entire cable, including the outerinsulated covering, which is held securely in hole 18, is firmly securedwithin body 3. The keys electrically ground the sheathing 16 to the case3, and any exterior contact with body 3 will not interfere withelectrical circuits passing through lead 14.

It will be noted that the above connections can be made easily andefliciently without the use of any special tools and particularlywithout the need for any soldered joints. Since the connection of thelead 14 to the central connector screw 8 is contained within the body 3all joints are protected from moisture and corrosion. Likewise, sincethe connections between the case 3, keys 2 and sheathing 16, arecontained within bore 24 they are likewise protected, and the connectoris substantially water proof.

I claim:

1. A connector, for attaching a threaded connector plug to a flexibleelectrical cable transmitting audio frequency electric impulses andhaving a central lead and a braided Wire sheathing insulated therefrom,composed of a susbtantially cylindrical body having a threaded outerbore at its outer connecting end and a threaded bore at its inner cableclamping end, said last mentioned bore 'having a taper at its inner endand longitudinal keyways on its inner walls and a smaller axialbore'connesting the bores in said end portions; cable clamping keysdisposed in said keyways; a threaded end plug screwed into the bore atsaid inner cable clamping end of said body, having an axial borereceiving said cable, and a bore within "its threaded end receiving the'outer portions of said keys and having a taper at its bottom; said keysbeing compressed into said cable by'engagement'of their respective endswith said'tapers in said body and said end plug when said end plug isthreaded into said inner body bore; ahead threaded into said outer boreof said body having an axial bore at its inner end and a threaded rim atits outer end to receive an attaching collar; a head bolt connectorextending axially in said inner head bore, and secured therein ininsulating relation to ed axially into the outer end of said head boltconnector,

securing said head bolt connector in insulated relation to said head;and an attaching collar screwed onto the outer end of said head; thehead of said conductor screw providing an axial contact, insulated fromsaid body and head and attaching collar when said collar is screwed ontosaid connector plug.

2. A connector, for removably attaching a flexible audio frequencytransmitting cable having a central lead and an outer grounded sheathinginsulated therefrom to a threaded connector fitting having a centralconductor, composed of a cylindrical body having a threaded outer boreat its outer end and a threaded bore witha tapered bottom shoulder atits inner cable attaching end, provided with longitudinal keywaygrooves; an end plug threaded into said bore at the cable attaching endof said body having an axial bore within its end adjacent said body saidbore being tapered at its bottom and an axial bore to receive atransmitting cable extending therefrom; keys for clamping the sheathingof an audio frequency transmitting cable disposed in said keyways withtheir ends engaging the tapers in the bores in said body and plug,respectively, and clamping on said cable when said plug is screwed intosaid body; a head threaded into the outer bore of said body having anenlarged axial bore within its end adjacent said body and a smaller boreextending outwardtherefrom; ahead bolt connector having a threaded innerend portion with a longitudinal groove and a tapered shoulder, disposedin said head bore in insulating relation thereto; a locking nut screwedon said head bolt having an inwardly tapered bore adjacent thettaperedshoulder on said head bolt, for securing the central conductor of saidcable in said head bolt and securing it on said shoulder; and an axialconductor insulated from said head and extending from its outer ;endportion to-said head bolt; said head having a'peripheral threaded meanson its outer end for attachment to a threaded connector fitting'so thatthe central conductor of said fitting is held in contact with said axialconduc tor'in said head.

3. A connector for removably attaching a flexible audio frequencytransmitting cable having a central lead and an .outer groundedsheathing, insulated therefrom, to a threaded connector fitting having acentral conductor, composed of a cylindrical body having a threadedouter end ,bore and a threaded inner end bore, ,a head havingan'insu'lated axial conductor terminating in a contact head adapted tocontact the central conductor of said connector fitting, a threadedouter flange provided with a collar for threaded attachment to saidconnector, threaded into the outer end of said body, a head bolt axiallypositioned within said head and insulated therefrom having an axialscrew and nut for clamping said central lead of said transmitting cable,an end plug axial- 1y receiving said cable screwed into said threadedinner end bore of said body, longitudinally extending cable clampingkeys compressed onto the sheathing of said cable by said end plug andsecuring said cable axially within said body, so that said central leadremains out of contact with said body, and said cable is retained withinsaid "body.

Belierences Cited in the file of this patent UNITED STATES PATENTS 12173,643 Moser Sept, 19, 1939 2 232,963 Papp et al. Feb. 25, 194-1FOREIGN PATENTS 205,930 Great Britain Nov; 1, 1923

